Home made collar? 22' offshore aluminum vessel

Discussion in 'Projects & Proposals' started by the brain, Jun 29, 2020.

  1. the brain
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    the brain Senior Member

    Home made collar?

    I would like advice for a home made foam collar made of this

    Cross Linked Polyethylene - 2LB https://www.foambymail.com/XPE2/cross-linked-polyethylene-foam-2lb.html

    4"x12"x48" 48" is the longest piece so maybe start off w/ 8' from stern well before midship.


    I do have white old fashioned Styrofoam under deck however there’s no telling how much the rodents have destroyed over the years.


    Also like the idea of added stability w/ reverse chine effect.


    1.Can I start off w/ stern to midship or must the collar be complete length of hull which is 22’.
    2.minimum thickness of foam to see results?
    3,I would like to remove majority of old Styrofoam under deck (for a belly fuel tank) and rely on the collar.
    4. how durable is this type foam I'm thinking it can't be used as a fender?
    5.outside of hull is painted concerned about saltwater being trapped in between hull & foam.
    6. kapten claims speed is increased & fuel consumption is reduced is appealing to me.

    I’m basically copying the kapten boat collar.


    Also considering a inflatable tube as a collar this would seriously widen the vessel and I’m not enthusiastic about constantly pumping it up.


    Thanks for any advice.
     
  2. kapnD
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    kapnD Senior Member

    That foam will require stout encapsulation as it is not very durable or even particularly strong in its raw state.
    How will it be fastened to the hull?
    How much will it weigh?
    How will it affect performance?
    Will the boat still be trailer able?
    The area under the gunnels is underutilized on many boats, and is a premium location for added flotation foam without hacking the whole design!
     
  3. the brain
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    the brain Senior Member

    yes you right there's nothing inside both gunnels except for control cables and hydraulics steering tubes on star side port there's nothing this space is kindof large probally 5"x12" so theres alot of unused space however the freeboard is 3' the vessel would be completely swamped before this area would effect flotation, guess it would help prevent complete sinking. and float level.
    was kindof wanting floatation low on hull to prevent a situation where the engine won't get swamped and disabled.

    the packageing foam wasn't my first choice. the life boats collar was however they won't sell to a none collared built vessel. I will be on the lookout for a crashed totalled life boat type vessel for it's tubes or a zodica type inflatable tube maybe filled w/ foam.

    LB tubes seam extremely durable so there's probably quite a bite of added weight.
    I've never been on a powered inflatable I'm thinking it's a much smoother ride conpared to solid huls.
    thanks
     
    Last edited: Jun 30, 2020
  4. the brain
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    the brain Senior Member

    I could fab this and have its seams welded for air tight pontoons. pontoon on side.jpg
     
  5. kapnD
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    kapnD Senior Member

    Typically, boats with flotation located under the floor will roll over when flooded.
    This is not a great scenario for occupants, they’ve got to hang on to the inverted boats bottom until rescue arrives.
    Flotation under the gunnels allows the boat to remain upright when flooded. Occupants will be wet, but still “in” the boat.
    Adding amas like on the Chrysler shown above will COMPLETELY change the way your boat behaves, and you may not like the changes!
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Adding foam to provide upright floating in the event of hull damage, is a different idea than trying to improve a boat by adding material externally, as mentioned that will change the boats behavior, and is liable to affect the ride adversely if not carefully executed. I very much doubt ride will be improved, but stability might be.
     

  7. the brain
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    the brain Senior Member

    yes you guys are probably correct on the handling is this because of the extra weight involved?

    I have plenty of white styrofoam to stuff up in the gunnels, still haven't gotton around to the styrofoam under the dive platform considering just using straps like how fuels tanks are attached to automobiles.

    I actually have a AB (zodica) inflatable where I could reuse the side tubes attached to the hull however each tube is only 5'.

    was thinking of attaching a PVC tube cut in half to hull that would secure the tube, tubes are like 15" diameter this would probablly smoothen the ride like riding on air.
     
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